”Proof of Life” is a thriller about hostage negotiators, but the movie’s most significant rescue mission may be revitalizing costar David Caruso’s career. Caruso’s spirited supporting performance as Russell Crowe’s reckless sidekick is reminding some critics what all the fuss was about back in 1993 when the temperamental redhead became TV’s hottest cop on ”NYPD Blue.” ”What’s neat for me is that people are finally focusing on my work again,” says Caruso, who’s now 44. ”It was, uh, complicated there for a while.”

The complications began when talk of Caruso’s prima donna behavior on the set of ”NYPD Blue” made its way to the press. Reports of his demands for endless retakes and an estimated $70,000 per episode raise at the end of the first season turned off many fans drawn in by his character Detective John Kelley’s soulful demeanor. (As a joke, Caruso pinned a ”Mr. Difficult” sign to the back of his chair on the set.) Caruso left the show during its second season to pursue a career as a leading man on the big screen, but the 1995 flops ”Jade” and ”Kiss of Death” (and later the short lived 1997 CBS TV series ”Michael Hayes”) turned his fall from grace into a late night TV punch line. ”I think it had a lot to do with the time that it happened, because there was no real precedent to fall back on for moving between the small screen and movies,” Caruso says.

”Proof” director Taylor Hackford, who first cast Caruso in his 1982 film ”An Officer and a Gentleman,” was one of the few willing to give the actor a second chance. ”He’s got a lot of demons, David does, and he’s put a lot of those demons to bed,” says the director, who declined to elaborate. Hackford, who recruited Crowe for help in casting the film, says the producers continued to see actors after Caruso’s audition, but couldn’t resist the jokey, war buddy chemistry between Caruso and Crowe. ”We saw a lot of really good actors for this role,” Hackford admits. ”But David came up to me and said, ‘I just want to do good work and work with good people,’ and that’s what it’s really about.” Crowe says simply of his costar: ”Caruso is crazy – in a good way – and it benefits the movie.”

Both actors had to do some serious preparation for ”Proof”’s mountaintop action sequences: They took physical training at high altitude, and met with hostage negotiators and military personnel to get the details right. Under such grueling conditions, Caruso says there was no room for divas. ”Look, I’m grateful that I got this picture,” he admits. ”Taylor didn’t have to cast me, and it’s great he trusted me to be in the movie. There aren’t a lot of big directors willing to put David Caruso in their movie.”

Though Caruso will next star in the low budget USA Films thriller ”Session 9” (scheduled for spring 2001), he isn’t expecting ”Proof” to make him as hot as he was in 1993. ”Yeah, like there’s hundreds of big movies being offered to me,” he jokes. ”If I can just stay in movies, that would be great.” Just not ”Jade 2,” okay?